Normally the lessons are in a pool and you then go outside in a lake or something for the first "real" dives.
The better solution, I think, is to learn it in the sea - it's far quicker (3-4 days) and more relaxing, when you do a course during your vacation.
The best "beginner-spots" I know are in Sharm el Sheik/Egypt. The reefs there are normally quite shallow, there's little or no current, the water is warm and clear and the courses are cheaper (at least than in Germany). And... all the colorful corals and fishes divert you from thoughts like "Oh my god - humans CAN'T breathe underwater"...
Edited by - Nixi on 20 August 2002 6:7:57